The field of the invention relates generally to electrical circuit protection devices, and more specifically to voltage surge protection devices and systems for electrical panelboards.
Various different types of circuit protectors exist to meet the needs of electrical power systems providing electrical power to various loads. Among these, surge suppression devices (SPDs) have been developed in response to the need to protect an ever-expanding number of circuits, and particularly electronic devices connected to those circuits from over-voltage conditions in line-side circuitry that may result, for example, from static discharge or lightning strikes. Over-voltage surges can damage or destroy unprotected consumer electronics or sophisticated electronic packages used in industrial and commercial applications. Indeed, it is not uncommon for electronic devices to include internal SPDs or surge protection features designed to protect the device from certain overvoltage conditions or surges, and also for line-side circuitry powering the electronic device in an electrical power distribution system to include SPDs. Examples of electrical equipment which typically utilize SPD devices include but are not limited to telecommunications system, computer systems and control systems.
In use, SPDs normally exhibit a high impedance, but when an over-voltage event occurs, the devices switch to a low impendence state so as to shunt or divert overvoltage-induced current to electrical ground. Damaging currents are therefore diverted from flowing to load-side circuitry, thereby protecting the corresponding equipment, loads and electronic devices from damage.
When SPDs are utilized in electrical panelboards, certain problems are presented, and improvements are desired.